The present invention relates to a film image reading system, which comprises a film projector for projecting a film image from film on a projection optical system and a mirror unit for projecting the projected film image of said film projector to a reading unit which outputs a reading copy from a copying machine by projecting the film image on a manuscript reading unit.
In recent years, various types of film image reading systems have been proposed, which read a film image on an ordinary digital color copying machine and output the image as a color copy. In such a system, the film image reading system is combined with the copying machine, where the film image is projected on a manuscript reading unit of the copying machine, and image information is taken up from the manuscript reading unit similarly to a manuscript image on a platen in an copying machine. Further, the image information copy is processed and outputted in the same manner as a copy of a color manuscript. In the following, description will be given on the arrangement and outline of a color copying machine for outputting color copy used in combination with a film image reading system, referring to the examples already proposed by the present applicant (e.g. Japanese Provisional Patent Applications No. 1-8967 and No. 1-99589).
FIG. 16 shows the entire arrangement of a color copying machine provided with a film image reading system.
The color copying machine shown in FIG. 16 is furnished with a base machine 30, which comprises a platen glass 31 where a manuscript is placed on an upper surface thereof, an image input terminal (IIT) 32, an electric system control housing 33, an image output terminal (IOT) 34, a paper tray 35, and a user interface (U/I). As optional items, there are provided an edit pad 61, an auto document feeder (ADF) 62, a sorter 63, and a film image reading system comprising a film projector (F/P) 64 and a mirror unit (M/U) 65.
The image input terminal 32 comprises an imaging unit 37, a wire 38 and a driving pulley 39. By a color filter in the imaging unit 37, the color of the image is separated to primary colors of B (blue), G (green) and R (red) of light. Image information of the color manuscript read by a CCD line sensor is converted to multi-gradation digital image signal BGR and is outputted to an image processing system. The image processing system is accommodated in the electric system control housing 33 and performs various process such as conversion, compensating, editing, etc. in order to improve color, gradation, fineness and other picture quality and reproducibility by inputting image signal of BGR. The image color is converted to primary colors of toner of Y (yellow), M (magenta), C (cyan) and K (black). Gradation toner signal of process color is converted to on/off binary toner signals and is outputted to the image output terminal 34. The image output terminal 34 is provided with a scanner 40 and a photosensitive belt 41, and the image signal is converted to an optical signal at a laser output unit 40a. A latent image corresponding to the manuscript image is formed on the photosensitive belt 41 through a polygon mirror 40b, F/.theta. lens 40c and a reflection mirror 40d, and the image is transferred to paper carried from a paper tray 35, and a color copy is discharged.
In the image output terminal 34, the photosensitive belt 41 is driven by a driving pulley 41a, and a cleaner 41b, a charger 41c, a developer 41d each for Y, M, C and K, and a transfer unit 41e are arranged around it, and a transfer system 42 is provided face-to-face to the transfer unit 41e. The paper sent from the paper tray 35 through paper carrying route 35a is caught. In case of a 4-color full-color copy, the transfer system 42 is rotated by 4 turns to transfer each latent image of YMCK on the paper. Then, the paper is fixed by a fixer 45 by sending it from the transfer system 42 through a vacuum carrier 43 and is discharged. SSI (single sheet inserter) 35b is to selectively feed paper manually to the paper carrying route 35a.
On the user interface 36, the user selects the desired function and instructs the condition for execution. It is provided with a color display 51 and a hard control panel 52. Direct instruction can be given by soft button on screen in combination with an infrared touch board 53.
The electric system control housing 33 is to accommodate a plurality of control boards arranged for each processing unit such as the image input terminal 32, the image output terminal 34, the user interface 36, the image processing system, the film projector 64, etc., and further, MCB boards (machine control boards) for controlling the operation of mechanisms such as the image output terminal 34, the automatic manuscript feeder 62, the sorter 63, etc., and SYS board for controlling the entire system.
Next, description will be given on the film projector 64 and the mirror unit 65, which constitute the film image reading system.
FIG. 17 represents perspective views of a film projector and a mirror unit, which constitute a film image reading system, and FIG. 18 is a schematical block diagram of the film image reading system.
As shown in FIG. 17(a), the film projector 64 is provided with a housing 601, and an operation checking lamp 602, a manual lamp switch 603, an auto-focus/manual-focus changeover switch (AF/MF changeover switch) 604, and manual-focus operation switches (M/F operation switches) 605a and 605b are furnished in the housing 601. Also, the housing 601 is provided with a closing unit 606 to open or close freely. On the top and the side of the closing unit 606, there are provided holes 608 and 609, through which a film holding case 607 for holding a manuscript film 633 is inserted from longitudinal or lateral direction into the housing 601 depending on how an object on the manuscript film 633 is photographed.
The film holding case 607 is furnished with a case for 35 mm negative film and a case of positive film, and the film projector 64 can match any of these films, and further, with negative films of 6 cm.times.6 cm or 4 inch.times.5 inch. The negative film is closely attached on a platen glass 31 between the mirror unit 65 and the platen glass 31.
As shown in FIG. 17(a), the mirror unit 65 is provided with a bottom plate 627 and a cover 628, one end of which is rotatably mounted on the bottom plate 627. Between the bottom plate 627 and the cover 628, a pair of supporters 629 and 629 are pivotally supported, and these supporters 629 and 629 support the cover 628 in such manner that the cover 628 and the bottom plate 627 form an angle of 45 degrees when the cover 628 is opened to the furthest extent.
A mirror 630 is mounted on rear side of the cover 628. A wide opening is formed on the bottom plate 627, and there are provided a Fresnel lens and a diffusion plate 632 as if they close the opening.
The Fresnel lens 631 and the diffusion plate 632 are made of a single acrylic resin plate. Fresnel lens 631 is formed on front surface of the acrylic resin plate, and the diffusion plate 632 is furnished on rear surface thereof. Fresnel lens 631 changes projected light, which is reflected by the mirror 630 and is going to diffuse to parallel beams, and prevents the darkening of peripheral portion of the image. The diffusion plate 632 also serves to diffuse the parallel beams to the slightest extent so that the shadow of Selfoc lens 224 in the imaging unit 37, forming by parallel beams from Fresnel lens 631, is not detected by a line sensor 226.
As shown in FIG. 18, a reflector 612 and a light source lamp 613 made of a halogen lamp are arranged in the housing 601 coaxially with a projection lens 610. Near the lamp 613, a cooling fan 614 for cooling the lamp 613 is furnished. Further, to the right of the lamp 613, there are provided coaxially with the projection lens 610, an aspherical lens 615 for converging light from the lamp 613, a heat absorbing filter 616 for cutting the light beam of a predetermined wavelength and a convex lens 617.
To the right of the convex lens 617, there is provided a compensating filter automatic replacing unit, which comprises a compensating filter holding member 618 for supporting a compensating filter 635 (A compensating filter for one of films is shown in the figure.), adjusting film density for 35 mm negative film and positive film, a driving motor 619 of the compensating filter holding member 618, and a first and a second position detection sensors 620 and 621 for detecting rotational position of the compensating filter holding member 618, and a control unit (provided in the film projector 64, but not shown) for controlling the driving motor 619. Of the compensating filters supported by the compensating filter holding member 618, a compensating filter 635 corresponding to the manuscript film 633 is automatically selected and is coordinated to a position coaxial with each of the lenses such as projection lens 610. The compensating filter 635 of this compensating filter automatic replacing unit can be arranged at any point on optical axis of the projected light, e.g. between the platen glass 31 and the imaging unit 37.
Further, there are provided a light emitter 623 for auto-focus sensor interlocked with a projection lens holding member 611 and a photodetector 624, and an auto-focus unit equipped with a sliding motor 625 for sliding the projection lens holding member 611 of the projection lens 610 with respect to the housing 601. When the film holding case 607 is inserted into the housing 601 through the holes 608 or 609, the manuscript film 633 supported by the film holding case 607 is positioned between the compensating film holding member 618 and the light emitter 623 or the photodetector 624. Near the setting position of the manuscript film 635, a film cooling fan 626 for cooling the manuscript film 633 is furnished.
Auto-fucus function (AF function) is to automatically focus when the manuscript 633 is placed in the film projector 64, and it is carried out as follows:
By turning to film projector mode through the key operation on display of a user interface 36, the light emitter 623 emits light. By selecting the AF/MF changeover switch 604 of the film projector 64 to AF, AF unit is ready to operate. When the film case 607 with the manuscript film 633 is placed in the film projector 64, the light from the light emitter 623 is reflected by the manuscript film 633, and the reflected light is detected by the photodetector 624 of 2-element type for AF.
The two elements of the photodetector 624 issue signals corresponding to the quantity of the detected reflected light. The difference between these signals is processed by analog computation by an analog comparator. If the result of the computation is not 0, output signal is issued, and a motor 625 is driven toward a direction to decrease the difference between the signals from the two elements. Therefore, when the projection lens holding member 611 is slid, the light emitter 623 and the photodetector 624 also move. When the difference between output signals from two elements turns to 0, CPU 634 stops the motor 625. The moment when the motor 625 stops is the moment of correct focusing.
Thus, AF operation is carried out. When the film case with the manuscript film is placed in the film projector 64, there is no need to focus manually each time. This not only saves working procedure but also prevents copying failure due to incorrect focusing.
In processing the image signal, a line sensor 226 reads projected light of an image of the manuscript 633 in analog as light quantity for R, G and B as shown in FIG. 18, and the image signal expressed by the light quantity is amplified to a desired level by an amplifier 231. The amplified image signal is converted to digital signal by an A/D converter 235 and is further converted to density signal from light quantity signal by a log converter 238.
The image signal given in density is compensated for shading by a shading compensation circuit 239. By this shading compensation, the image signal is cleared from uneven light quantity on Selfoc lens 224, uneven sensitivity of each pixel in the line sensor 226, variations in spectral characteristics and light quantity level in compensating filter or lamp 613, and the influence of the changes over time.
Prior to the shading compensation, if the above three types of film and registered film are selected as the manuscript film, the compensating filter is set to the filter for positive film, and light quantity signal from the lamp 613 is read with the manuscript film 633 not placed in position. After amplifying the signal and converting to digital signal, the data obtained from the data converted to density signal are stored in a line memory 240 as reference data. Specifically, the imaging unit 37 is sampled by 16-line step scanning for each pixel of R, G and B, and these sampling data are sent to CPU 634 through the line memory 240. CPU 634 computes average density value of each pixel of the sampling data of 16 lines and obtains shading data. By this averaging, influence of dust and the like on diffusion plate contained on the read data for each line can be reduced.
When the manuscript film is positioned in place and the image of the manuscript film is read, CPU 634 computes density adjustment value D.sub.ADj from density data of negative film memorized in ROM, and D.sub.ADj value set in register of LSI in the shading compensation circuit 239 is altered. Further, CPU 634 adjusts light quantity of the lamp 613 and gain of the amplifier 643 according to the selected film.
The shading compensation circuit 239 shifts the density value by adding D.sub.ADj value to actual data read from the manuscript film. Further, the shading compensation circuit 239 performs shading compensation by drawing the shading data for each pixel from the adjusted data. When shading compensation is completed, the image input terminal 32 issues density signals of R, G and B to the image processing system 33. Based on actual data of the manuscript film, CPU 634 selects END curve, and compensating signal for .gamma. compensation is issued according to the selected curve. By this compensating signal, the image processing system 33 performs .gamma. compensation and corrects that .gamma. is not 1 in the manuscript film or vague contrast due to non-linear characteristics. Further, negative image is converted to positive image.
When copying is to be made on paper of maximum size, e.g. A3 size paper in a copying machine, the paper is longer in lateral direction. For this reason, if a film image is projected to read image information and is to be copied, it is necessary to obtain the projected image in the lateral direction to match the direction of the paper. However, even in case copying is to be made on A3 size paper longer in lateral direction, if copying is made only on one-half of one side, the projected image must be in longitudinal direction. In case two or more copies are made on A4 size paper, copying can be made at higher copying speed (cpm) when the paper is placed longer in longitudinal direction to obtain a longitudinal projected image than a lateral projection image.
For this reason, in a conventional type film image reading system to output color copies of film image, holes 608 and 609 are provided on upper and lower surfaces and left and right surfaces of the closing unit 606 of the housing 601 in order that longitudinal and lateral projection images can be obtained to match paper size and the direction of the paper. As the result, the film holding case 607 can be inserted into the housing 601 both from longitudinal and lateral directions. This causes the problem of dead space and the housing 601 needs to be larger. Particularly, in case of longitudinal projection, the film holding case 607 enters deep below the film projector 64. If other structures such as sorter are optionally installed as in the conventional case, interference with these structures occurs, and system layout is changed.
Further, film image is often inclined due to the conditions at the time of photographing. When such inclined film image is to be copied, it is possible according to the conventional type film image reading system only to select either longitudinal or lateral projection, and it is not possible to rotate the image as desired. In a real time combination with a copying machine, even when it is attempted to copy by overlapping the film image on a predetermined area of the manuscript using editing function, the film image can be only turned in longitudinal or lateral direction, and it cannot be inclined. This restricts the degree of freedom in editing. To achieve image rotation, image processing for rotating the image must be carried out in an image processing system, and this leads to more complicated and troublesome data processing.
In a film image reading system where it is possible to rotate the image, when a scaling-down optical system is combined with the film image reading system, optical image is too dark on the projection plane and it is difficult to confirm rotating angle of the image. To check whether the desired image rotating angle has been obtained or not, it is necessary to make the checking of the image easier by placing a piece of white paper below Fresnel lens.
As described above, in the film image reading system, a mirror unit is set at a predetermined distance from the film projector in order to maintain necessary optical path and to project the projection image of the film projector on a reading unit. Thus, when the film image reading system is not used, the mirror unit causes a mess and there arises a problem of space.
Moreover, in a conventional type film image reading system, auto-focus function is provided, in which focusing is performed through partial feedback system using an analog comparator so that the positional relation between the film and the lens is kept at constant level by a position detection sensor comprising of a light emitter and a photodetector using reflected light as described above. Because the feedback loop is small, response time is short. Because no intervention of software is required, there is no need to think about convergence. Further, because response time is short, auto-focusing can be performed for each copy even when two or more copies are needed. Also, warping of film due to heat can be reduced. However, to obtain maximum resolution, it is necessary to perform initial adjustment for adjusting relative position of lens and auto-focus optical system to attain the optimal focusing at the position under control of manual feedback system.
However, in manual focusing, an image of the manuscript film 633 is projected on a diffusion plate 632 of the mirror unit 65, which is set at a predetermined position of the platen glass 31, and the projection lens holding member 611 is slid while watching the projected image. Accordingly, the image projected on the diffusion plate 632 is faint and difficult to discern, and it is very difficult to focus correctly. When it is attempted to achieve the best focusing by independently controlling the relations of film-lens and lens-projection plane, projection scale is not constant any more.